Makefile: add local.properties, fix clean

Makefile

 #!/bin/sh
 
 APP=bin/SFLPhoneHome-debug.apk
-all: $(APP)
-
-$(APP):
-	./make_swig.sh
+all: local.properties
 	ndk-build -C jni -j4
 	ant debug
 
+local.properties:
+	android update project -p .
+
 # You may want to specify a device with -s SERIAL NUMBER
 install: $(APP)
 	adb install -r $^
 
 clean:
-	rm -rf libs obj
+	rm -rf obj